#define _CRT_SECURE_NO_WARNINGS 1

#include <iostream>
using namespace std;
#include <vector>
#include <algorithm>

int main()
{
	int t = 0;
	cin >> t;
	while (t--) 
	{
		int n = 0;
		cin >> n;
		string s;
		cin >> s;
		string t;
		cin >> t;

		long long ans = 0;
		int s1[26] = { 0 };
		int t1[26] = { 0 };
		for (int i = 0; i < n; i++) {
			s1[s[i] - 'a']++;
			t1[t[i] - 'a']++;
		}
		
	}
	return 0;
}